SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 10)*

                                CABOT CORPORATION
                                (Name of Issuer)

                     COMMON STOCK, PAR VALUE $1.00 PER SHARE
                         (Title of Class of Securities)

                                    127055101
                                 (CUSIP Number)

                               SPO Advisory Corp.
                         591 Redwood Highway, Suite 3215
                          Mill Valley, California 94941
                                 (415) 383-6600

                                 with a copy to:

                                Alison S. Ressler
                             Sullivan & Cromwell LLP
                             1888 Century Park East
                       Los Angeles, California 90067-1725
                                 (310) 712-6600

           (Name, Address and Telephone Number of Person Authorized to
                       Receive Notices and Communications)

                                  May 28, 2009
             (Date of Event which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
Schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following
box |_|.

Note. Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).



                                                              Page 2 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         SPO Partners II, L.P.
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         WC
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         Delaware
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 5,913,400 (1)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 5,913,400 (1)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,913,400
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.0%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         PN
--------------------------------------------------------------------------------

(1) Power is exercised through its sole general partner, SPO Advisory Partners,
    L.P.


                                                              Page 3 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         SPO Advisory Partners, L.P.
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         Not Applicable
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         Delaware
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 5,913,400 (1)(2)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 5,913,400 (1)(2)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,913,400
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.0%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         PN
--------------------------------------------------------------------------------

(1) Solely in its capacity as the sole general partner of SPO Partners II, L.P.
(2) Power is exercised through its sole general partner, SPO Advisory Corp.


                                                              Page 4 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         SPO Advisory Corp.
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         Not Applicable
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         Delaware
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 5,913,400 (1)(2)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 5,913,400 (1)(2)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,913,400
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.0%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         CO
--------------------------------------------------------------------------------

(1) Solely in its capacity as the sole general partner of SPO Advisory
    Partners, L.P. with respect to 5,913,400 of such shares.

(2) Power is exercised through its four controlling persons, John H. Scully,
    William E. Oberndorf, William J. Patterson and Edward H. McDermott.


                                                              Page 5 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         John H. Scully
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         Not Applicable
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         USA
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 -0-
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            5,913,400 (1)
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 -0-
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 5,913,400 (1)
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,913,400
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.0%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         IN
--------------------------------------------------------------------------------

(1) These shares may be deemed to be beneficially owned by Mr. Scully solely
    in his capacity as one of four controlling persons of SPO Advisory Corp.


                                                              Page 6 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         William E. Oberndorf
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         Not Applicable and PF
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         USA
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 176,700 (1)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            6,247,050 (2)
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 176,700 (1)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 6,247,050 (2)
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         6,423,750
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.8%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         IN
--------------------------------------------------------------------------------

(1) Of these shares, 66,700 shares are held in William E. Oberndorf's
Individual Retirement Account, which is self-directed, 100,000 shares may be
deemed to be beneficially owned by Mr. Oberndorf solely in his capacity as sole
general partner of Oberndorf Family Partners, a family partnership, and 10,000
shares are owned by Mr. Oberndorf solely in his capacity as trustee for the
account of his children.

(2) Of these shares, 5,913,400 shares may be deemed to be beneficially owned by
Mr. Oberndorf solely in his capacity as one of the four controlling persons of
SPO Advisory Corp., and 333,650 shares may be deemed to be beneficially owned by
Mr. Oberndorf solely in his capacity as a trustee of the William and Susan
Oberndorf Trust, dated 10/19/98.


                                                              Page 7 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         William and Susan Oberndorf Trust, dated 10/19/98
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         PF
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEM 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         California
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 333,650 (1)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 333,650 (1)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         333,650 (1)
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         0.5%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         OO
--------------------------------------------------------------------------------

(1) Power is exercised through its trustees, William E. Oberndorf and Susan C.
Oberndorf.


                                                             Page 8 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         Oberndorf Family Partners
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         WC
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         California
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 100,000 (1)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 100,000 (1)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         100,000 (1)
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         0.2%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         PN
--------------------------------------------------------------------------------

(1) Power is exercised through its sole general partner, William E. Oberndorf.


                                                             Page 9 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         William J. Patterson
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         Not Applicable
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         USA
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 -0-
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            5,926,800 (1)
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 -0-
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 5,926,800 (1)
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,926,800
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.1%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         IN
--------------------------------------------------------------------------------

(1) Of these shares, 5,913,400 shares may be deemed to be beneficially owned by
Mr. Patterson solely in his capacity as one of the four controlling persons of
SPO Advisory Corp. and 13,400 shares may be deemed to be beneficially owned by
Mr. Patterson solely in his capacity as a controlling person, director and
executive officer of the Elizabeth R. & William J. Patterson Foundation.


                                                             Page 10 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         The Elizabeth R. & William J. Patterson Foundation
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         WC
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         CALIFORNIA
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 13,400 (1)
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 13,400 (1)
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         13,400
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         **0.1%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         CO
--------------------------------------------------------------------------------

** Denotes less than.

(1) Power is exercised through its controlling persons, directors and executive
officers, William J. Patterson and Elizabeth R. Patterson.



                                                             Page 11 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         Edward H. McDermott
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         Not Applicable
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         USA
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 -0-
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            5,913,400 (1)
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 -0-
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 5,913,400 (1)
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,913,400
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         9.0%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         IN
--------------------------------------------------------------------------------

(1) These shares may be deemed to be beneficially owned by Mr. McDermott solely
    in his capacity as one of four controlling persons of SPO Advisory Corp.


                                                             Page 12 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         Ian R. McGuire
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         PF
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         CALIFORNIA
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 475
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 475
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         475
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         **0.1%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         IN
--------------------------------------------------------------------------------

** Denotes less than.


                                                             Page 13 of 21 pages
CUSIP No. 127055101

--------------------------------------------------------------------------------
1.       NAME OF REPORTING PERSON
         Betty Jane Weimer
--------------------------------------------------------------------------------
2.       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:           (a)     |_|
                                                                     (b)     |X|
--------------------------------------------------------------------------------
3.       SEC Use Only
--------------------------------------------------------------------------------
4.       SOURCE OF FUNDS
         PF
--------------------------------------------------------------------------------
5.       CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
         ITEMS 2(d) OR 2(e) |_|
--------------------------------------------------------------------------------
6.       CITIZENSHIP OR PLACE OF ORGANIZATION
         California
--------------------------------------------------------------------------------
                          7.     SOLE VOTING POWER
                                 5,000
                          ------------------------------------------------------
Number Of Shares          8.     SHARED VOTING POWER
Beneficially Owned By            -0-
Each Reporting Person     ------------------------------------------------------
With                      9.     SOLE DISPOSITIVE POWER
                                 5,000
                          ------------------------------------------------------
                          10.    SHARED DISPOSITIVE POWER
                                 -0-
--------------------------------------------------------------------------------
11.      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,000
--------------------------------------------------------------------------------
12.      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
         SHARES |_|
--------------------------------------------------------------------------------
13.      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
         **0.1%
--------------------------------------------------------------------------------
14.      TYPE OF REPORTING PERSON
         IN
--------------------------------------------------------------------------------

** Denotes less than.


                                                             Page 14 of 21 pages

         This Amendment No. 10 amends the Schedule 13D (the "Original 13D")
filed with the Securities and Exchange Commission ("SEC") on August 29, 2005 and
as amended on September 14, 2005, September 26, 2005, October 20, 2005, November
8, 2005, January 12, 2006, June 20, 2006, December 18, 2007, January 4, 2008 and
August 12, 2008. Unless otherwise stated herein, the Original 13D, as previously
amended, remains in full force and effect. Terms used herein and not defined
herein shall have the meanings ascribed thereto in the Original 13D.

ITEM 2. IDENTITY AND BACKGROUND.

         Item 2(a) is hereby amended and restated in its entirety as follows:

         (a) The undersigned hereby file this Schedule 13D Statement on behalf
of SPO Partners II, L.P., a Delaware limited partnership ("SPO"), SPO Advisory
Partners, L.P., a Delaware limited partnership ("SPO Advisory Partners"), SPO
Advisory Corp., a Delaware corporation ("SPO Advisory Corp."), John H. Scully
("JHS"), William E. Oberndorf ("WEO"), William J. Patterson ("WJP"), Edward H.
McDermott ("EHM"), the William and Susan Oberndorf Trust, dated 10/19/98
("Oberndorf Trust"), Oberndorf Family Partners, a California limited partnership
("OFP"), the Elizabeth R. & William J. Patterson Foundation, a California
corporation ("Patterson Foundation"), Ian R. McGuire ("IRM") and Betty Jane
Weimer ("BJW"). SPO, SPO Advisory Partners, SFP, SF Advisory Partners, SPO
Advisory Corp., JHS, WEO, WJP, EHM, the Oberndorf Trust, OFP, Patterson
Foundation, IRM and BJW are sometimes hereinafter referred to as the "Reporting
Persons." The Reporting Persons are making this single, joint filing because
they may be deemed to constitute a "group" within the meaning of Section
13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act"),
although neither the fact of this filing nor anything contained herein shall be
deemed to be an admission by the Reporting Persons that a group exists. San
Francisco Partners II, L.P., a California limited partnership ("SFP"), and SF
Advisory Partners, L.P., a Delaware limited partnership ("SF Advisory
Partners"), who previously reported holdings under the last amendment to the
Original 13D, have subsequently sold all their holdings in the Issuer and
therefore are not reporting beneficial ownership of Shares in this Amendment
No. 10.

         The subsections with respect to SFP and SF Advisory Partners of Item
2(b)-(c) are hereby deleted in their entirety.



                                                             Page 15 of 21 pages


ITEM 3.  SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

         Item 3 is hereby amended and restated in its entirety as follows:

         The source and amount of the funds used or to be used by the Reporting
Persons to purchase Shares are as follows:

NAME                        SOURCE OF FUNDS                  AMOUNT OF FUNDS
---------------------       ---------------------------      ---------------
SPO                         Contributions from Partners         $252,908,717
SPO Advisory Partners       Not Applicable                    Not Applicable
SPO Advisory Corp.          Not Applicable                    Not Applicable
JHS                         Not Applicable                    Not Applicable
WEO                         Not Applicable and
                              Personal Funds (1)                $  4,718,794
WJP                         Not Applicable                    Not Applicable
EHM                         Not Applicable                    Not Applicable
Oberndorf Trust             Personal Funds (1)                  $ 12,237,424
OFP                         Contribution from Partners          $  3,635,448
Patterson Foundation        Contributions from Shareholders         $583,185
IRM                         Personal Funds (1)                       $16,877
BJW                         Personal Funds (1)                  $    186,594

----------
(1) As used herein, the term "Personal Funds" includes sums borrowed from banks
and brokerage firm margin accounts, none of which were borrowed or otherwise
obtained for the specified purpose of acquiring, holding, trading or voting
Shares.

ITEM 5.  INTEREST IN SECURITIES OF THE ISSUER.

         Item 5 is hereby amended and restated in its entirety as follows:

         (a) Percentage interest calculations for each Reporting Person are
based upon the Issuer having 65,401,025 total outstanding shares of Common Stock
as reported on the Issuer's 10-Q filed with the Securities and Exchange
Commission on May 11, 2009.

         SPO

         The aggregate number of Shares that SPO owns beneficially, pursuant to
Rule 13d-3 of the Act, is 5,913,400 Shares, which constitutes approximately
9.0% of the outstanding Shares.

         SPO Advisory Partners

         Because of its position as the sole general partner of SPO, SPO
Advisory Partners may, pursuant to Rule 13d-3 of the Act, be deemed to be the
beneficial owner of 5,913,400 Shares, which constitutes approximately 9.0% of
the outstanding Shares.

         SPO Advisory Corp.

         Because of its position as the sole general partner of SPO Advisory
Partners, SPO Advisory Corp. may, pursuant to Rule 13d-3 of the Act, be deemed
to be the beneficial owner of 5,913,400 Shares in the aggregate, which
constitutes approximately 9.0% of the outstanding Shares.

         JHS

         Because of his position as a control person of SPO Advisory Corp., JHS
may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of
5,913,400 Shares, which constitutes approximately 9.0% of the outstanding
Shares.

         WEO

         Individually, and because of his positions as a control person of SPO
Advisory Corp., a trustee of the Oberndorf Trust and sole general partner of OFP
and as trustee for the account of his children, WEO may, pursuant to Rule 13d-3
of the Act, be deemed to be the beneficial owner of 6,423,750 Shares in the
aggregate, which constitutes approximately 9.8% of the outstanding Shares.



                                                             Page 16 of 21 pages

         WJP

         Because of his position as a control person of SPO Advisory Corp. and
as a control person, director and executive officer of Patterson Foundation, WJP
may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of
5,926,800 Shares, which constitutes approximately 9.1% of the outstanding
Shares.

         EHM

         Because of his position as a control person of SPO Advisory Corp., EHM
may, pursuant to Rule 13d-3 of the Act, be deemed to be the beneficial owner of
5,913,400 Shares, which constitutes approximately 9.0% of the outstanding
Shares.

         Oberndorf Trust

         The aggregate number of Shares that the Oberndorf Trust owns
beneficially, pursuant to Rule 13d-3 of the Act, is 333,650 Shares, which
constitutes approximately 0.5% of the outstanding Shares.

         OFP

         The aggregate number of Shares that OFP owns beneficially, pursuant to
Rule 13d-3 of the Act, is 100,000 Shares, which constitutes approximately 0.2%
of the outstanding Shares.

         Patterson Foundation

         The aggregate number of Shares that Patterson Foundation owns
beneficially, pursuant to Rule 13d-3 of the Act, is 13,400, which constitutes
less than 0.1% of the outstanding Shares.

         IRM

         The aggregate number of Shares that IRM owns beneficially, pursuant to
Rule 13d-3 of the Act, is 475 Shares, which constitutes less than 0.1% of the
outstanding Shares.

         BJW

         The aggregate number of Shares that BJW owns beneficially, pursuant to
Rule 13d-3 of the Act, is 5,000 Shares, which constitutes less than 0.1% of the
outstanding Shares.

         To the best of the knowledge of each of the Reporting Persons, other
than as set forth above, none of the persons named in Item 2 hereof is the
beneficial owner of any Shares.

         (b) SPO

         Acting through its sole general partner, SPO has the sole power to vote
or to direct the vote and to dispose or to direct the disposition of 5,913,400
Shares.

         SPO Advisory Partners

         Acting through its sole general partner and in its capacity as the sole
general partner of SPO, SPO Advisory Partners has the sole power to vote or to
direct the vote and to dispose or to direct the disposition of 5,913,400
Shares.



                                                             Page 17 of 21 pages

         SPO Advisory Corp.

         Acting through its controlling persons and in its capacity as the sole
general partner of SPO Advisory Partners, SPO Advisory Corp. has the sole power
to vote or to direct the vote and to dispose or to direct the disposition of
5,913,400 Shares in the aggregate.

         JHS

         As one of four controlling persons of SPO Advisory Corp., which is the
sole general partner of SPO Advisory Partners, JHS may be deemed to have shared
power with WEO, WJP and EHM to vote or to direct the vote and to dispose or to
direct the disposition of 5,913,400 Shares held by SPO and SFP in the aggregate.

         WEO

         As one of four controlling persons of SPO Advisory Corp., which is the
sole general partner of SPO Advisory Partners, WEO may be deemed to have shared
power with JHS, WJP and EHM to vote or to direct the vote and to dispose or to
direct the disposition of 5,913,400 Shares held by SPO and SFP in the aggregate.
WEO may be deemed to have shared power to vote or to direct the vote and to
dispose or to direct the disposition of 333,650 Shares held in the Oberndorf
Trust. Individually, and because of his position as the sole general partner of
OFP, WEO has the sole power to vote or to direct the vote and to dispose or to
direct the disposition of 66,700 Shares held in WEO's Individual Retirement
Account, which is self directed, and 100,000 Shares held by OFP. Solely in his
capacity as trustee for the account of his children, WEO has the sole power to
vote or to direct the vote and to dispose or to direct the disposition of 10,000
shares owned by his children.

         WJP

         As one of four controlling persons of SPO Advisory Corp., which is the
sole general partner of SPO Advisory Partners, WJP may be deemed to have shared
power with JHS, WEO and EHM to vote or to direct the vote and to dispose or to
direct the disposition of 5,913,400 Shares held by SPO and SFP in the aggregate.
WJP may be deemed to have shared power to vote or to direct the vote and to
dispose or to direct the disposition of 13,400 Shares held by the Patterson
Foundation.

         EHM

         As one of four controlling persons of SPO Advisory Corp., which is the
sole general partner of SPO Advisory Partners, EHM may be deemed to have shared
power with JHS, WEO and WJP to vote or to direct the vote and to dispose or to
direct the disposition of 5,913,400 Shares held by SPO and SFP in the aggregate.




                                                             Page 18 of 21 pages

         Oberndorf Trust

         Acting through its trustees, Oberndorf Trust has the sole power to vote
or to direct the vote and to dispose or to direct the disposition of 333,650
Shares in the aggregate.

         OFP

         OFP has the sole power to vote or to direct the vote and to dispose or
to direct the disposition of 100,000 Shares.

         Patterson Foundation

         Acting through its two controlling persons, directors and executive
officers, Patterson Foundation has the sole power to vote or to direct the vote
and to dispose or to direct the disposition of 13,400 Shares.

         IRM

         IRM has the sole power to vote or to direct the vote and to dispose or
to direct the disposition of 475 Shares.

         BJW

         BJW has the sole power to vote or to direct the vote and to dispose or
to direct the disposition of 5,000 Shares.

         (c) During the past 60 days, the Reporting Persons purchased Shares in
open market transactions as set forth on Schedule I attached hereto.

         Except as set forth in this paragraph (c), to the best of the knowledge
of each of the Reporting Persons, none of the persons named in response to
paragraph (a) has effected any transactions in Shares during the past 60 days.

         (d) Each of the Reporting Persons affirms that no person other than
such Reporting Person has the right to receive or the power to direct the
receipt of distributions with respect to, or the proceeds from the sale of,
Shares owned by such Reporting Person.

         (e) Not applicable.

ITEM 7.  MATERIAL TO BE FILED AS EXHIBITS.

Item 7 is hereby amended and restated in its entirety as follows:

Exhibit A:   Agreement pursuant to Rule 13d-1(k)




                                                             Page 19 of 21 pages

                                    SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


Dated June 1, 2009                         By:       /s/ Kim M. Silva
                                               --------------------------------
                                                   Kim M. Silva

                                           Attorney-in-Fact for:

                                           SPO PARTNERS II, L.P.(1)
                                           SPO ADVISORY PARTNERS, L.P.(1)
                                           SPO ADVISORY CORP.(1)
                                           JOHN H. SCULLY(1)
                                           WILLIAM E. OBERNDORF(1)
                                           WILLIAM J. PATTERSON(1)
                                           EDWARD H. MCDERMOTT(1)
                                           WILLIAM AND SUSAN OBERNDORF TRUST,
                                              DATED 10/19/98 (1)
                                           OBERNDORF FAMILY PARTNERS (1)
                                           THE ELIZABETH R. & WILLIAM J.
                                             PATTERSON FOUNDATION (1)
                                           IAN R. MCGUIRE (1)
                                           BETTY JANE WEIMER (1)

                                           (1) A Power of Attorney
                                           authorizing Kim M. Silva to
                                           act on behalf of this
                                           person or entity has been previously
                                           filed with the Securities and
                                           Exchange Commission.



                                                             Page 20 of 21 pages



                                               SCHEDULE I TO SCHEDULE 13D

                                                                                   NUMBER
                                      DATE OF                         OF        PRICE PER      WHERE/HOW TRANSACTION
REPORTING PERSON                    TRANSACTION        TYPE         SHARES      SHARE ($)            EFFECTED
-------------------------------     -----------        ----         ------      ---------      ---------------------
                                                                                
SPO Partners II, L.P.               5/28/2009          Sell         3,749,200   15.60          Privately Negotiated Transaction
William E. Oberndorf IRA            5/28/2009          Sell            42,300   15.60          Privately Negotiated Transaction
The Elizabeth R. & William
     J. Patterson Foundation        5/28/2009          Sell             8,500   15.60          Privately Negotiated Transaction




                                                            Page 21 of 21 pages

                                  EXHIBIT INDEX

EXHIBIT     DOCUMENT DESCRIPTION
-------     ------------------------------------
A           Agreement Pursuant to Rule 13d-1(k)